The proposed 3-phase study aims to investigate clinical correlates of anxiety and identify points of intervention for advanced non-small cell lung cancer (NSCLC) patients and their primary caregivers. Employing a mixed methods approach, we will develop and test the feasibility and acceptability of a dyadic cognitive- behavioral therapy (CBT) intervention to reduce anxiety in patients and their caregivers. Significance: Anxiety is prevalent, distressing, understudied, and predicts mental and physical health outcomes in NSCLC patients and their primary informal caregivers. Preliminary research has found rates of elevated anxiety to be 35% in patients with advanced NSCLC and 50% in their primary caregivers. In addition, anxiety between the patient and the caregiver is mutual and reciprocal; if one member of the dyad has poorly controlled anxiety, the other is at risk as well. While a small number of behavioral medicine interventions have been effective in reducing distress in cancer patients and caregivers independently, few interventions to date have been developed that address anxiety specifically, and none treat both patients and caregivers simultaneously. CBT is a widely-studied, evidence-based treatment for anxiety; development of a dyadic CBT intervention to reduce anxiety in advanced NSCLC patients and their primary caregivers is necessary to reduce a prevalent mental health problem that significantly impacts NSCLC patients and their families. Research Plan: The proposed study has three phases and is based on the Dyadic Stress-Coping Model of Anxiety in Cancer. 1) For the quantitative phase, an existing data set of 722 dyads (N=1,444) of advanced cancer patients and their caregivers will be analyzed to identify clinical correlates of anxiety. 2) For the qualitative phase, 10 patient-caregivers dyads (N=20) will be interviewed regarding cancer- and care giving- related anxiety to further refine points of intervention and components of a targeted CBT intervention. 3) Finally, 5 dyads (N=10) will pilot test the feasibility and acceptability of the resulting CBT intervention. Environment: Study participants will be recruited from the Massachusetts General Hospital Cancer Center (MGHCC), a quaternary care medical center with ample patient availability and a demonstrated track record of psychosocial study participation. The P.I., a new investigator, will receive mentorship from a team of nationally recognized researchers in CBT interventions for medical comorbidity, assessment of psychosocial variables among advanced cancer patients and caregivers, conduct of behavioral research in cancer care settings, qualitative methodology regarding end-of-life care, and intervention design for anxiety in advanced cancer. The investigators will access clinical research resources from the MGH Center for Psychiatric Oncology and Behavioral Science and the Behavioral Medicine Service within the Department of Psychiatry. Relevance: The proposed study responds to NCI's FOA PAR-09-003 to develop interventions that prevent or control negative outcomes and improve quality of life among cancer patients and their caregivers.